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Block Timestamp Manipulation

block.timestamp می تواند توسط ماینرها با محدودیت های زیر دستکاری شود

  • نمی توان آن را با زمان زودتر از والد خود مهر کرد
  • در آینده نمی تواند خیلی دور باشد

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.24;

Roulette is a game where you can win all of the Ether in the contract
if you can submit a transaction at a specific timing.
A player needs to send 10 Ether and wins if the block.timestamp % 15 == 0.

1. Deploy Roulette with 10 Ether
2. Eve runs a powerful miner that can manipulate the block timestamp.
3. Eve sets the block.timestamp to a number in the future that is divisible by
   15 and finds the target block hash.
4. Eve's block is successfully included into the chain, Eve wins the
   Roulette game.

contract Roulette {
    uint256 public pastBlockTime;

    constructor() payable {}

    function spin() external payable {
        require(msg.value == 10 ether); // must send 10 ether to play
        require(block.timestamp != pastBlockTime); // only 1 transaction per block

        pastBlockTime = block.timestamp;

        if (block.timestamp % 15 == 0) {
            (bool sent,) ={value: address(this).balance}("");
            require(sent, "Failed to send Ether");

روی محیط توسعه ی Remix امتحان بکنید

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